Semiconductor chip installing tape, semiconductor device and a method for fabricating thereof

ABSTRACT

A semiconductor chip mounting tape on which external connecting terminals are formed in accordance with a layout pattern has post portions which are to be connected to a semiconductor chip and external connecting terminals. Post portoins are formed on the first surface of an insulation tape used as a base of the semiconductor chip mounting tape. External connecting terminals are formed on the second surface of the insulation tape. The post portions and the external connecting terminals are integrally formed by same solder balls via through holes formed in the insulation tape.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a semiconductor chip package such as aball (or bump) grid array (BGA) package, a semiconductor chip mountingtape particularly, and also to a semiconductor device, and fabricatingmethods.

[0003] 2. Description of Related Art

[0004] In BGA packages, circuit patterns are formed on both sides of asubstrate (or a tape) and a semiconductor chip is mounted on the surfaceof the substrate.

[0005] For the electrical connection of the semiconductor chip mountedon the substrate, pads formed on the semiconductor chip and leads formedon the surface of the substrate are electrically connected by wire bonds(or bumps in the case of a flip chip system) and a connecting portion isprotected by a resin seal formed by a method such as molding, potting,or the like.

[0006] Solder balls serving as external connecting terminals are formedon the circuit pattern on the back side of the substrate in accordancewith a predetermined layout pattern.

[0007] The solder ball is temporarily fixed to a predetermined positionby a ball mounter by using a flux, thereafter, reflowed through afurnace, and fixedly bonded onto the substrate, thereby forming theexternal connecting terminal.

[0008] With regard to the external connecting terminals, the diameter ofthe ball is reduced due to demands for miniaturization of the packageand use of multi-pins, and the adoption of a narrower pitch of terminalsis also occurring.

[0009]FIG. 1 is a cross sectional view showing a state where a solderballs are held by vacuum at a vacuum plate of the conventional ballmounter. The mounting of solder balls 1 by the ball mounter is performedby using the vacuum plate 2.

[0010] Vacuum holes 4 having tapered portions 3 are formed in the vacuumplate 2 in accordance with the layout pattern of the pads on the backside of the substrate, thereby holding the solder balls 1 by vacuumevacuating by an apparatus (not shown).

[0011] The solder balls 1 are subsequently deposited on the substrate bya method whereby a flux 5 is transferred to the solder balls 1 and thesolder balls 1 are temporarily fixed onto the pads of the substrate byan adhering force of the flux 5.

[0012] However, a problem occurs in that the diameter of the solder ball1 decreases and the flux 5 transferred to the solder ball 1 is depositedto the tapered portion 3 of the vacuum plate 2. As a result, separationof the solder balls 1 from the vacuum plate 2 is disturbed or hinderedby the flux, and the solder ball 1 cannot be deposited surely onto thepad of the substrate.

[0013] When, on the other hand, the solder balls 1 have a reduceddiameter, the transfer amount of the flux to the solder ball 1decreases, so that fouling such as an oxide film on the pad of thesubstrate cannot be sufficiently removed by the flux. This will resultin degrading of the fusing state of the solder at the time of the reflowprocess. Thus, there also is a problem that the solder ball 1 dropsbecause the solder is insufficiently fused.

OBJECTS AND SUMMARY OF THE INVENTION

[0014] To solve the above problems, according to the invention, postportions to be connected to semiconductor chips are formed on a firstsurface of a tape having an insulation characteristic, which will bereferred to as insulation tape, external connecting terminals are formedon a second surface of the insulation tape, and the post portions andthe external connecting terminals are integrally formed by solder ballspiercing through holes formed in the insulation tape.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a cross sectional view showing solder balls held byvacuum in a conventional arrangement;

[0016]FIGS. 2 and 3 are diagrams showing a semiconductor chip mountingtape according to the invention, in which FIG. 2 is a plan view and FIG.3 is a cross sectional view;

[0017]FIG. 4 is an enlarged cross sectional view of a part of thesemiconductor chip mounting tape shown in FIGS. 2 and 3;

[0018]FIG. 5 is a plan view showing a state where through holes areformed in an insulation tape;

[0019]FIG. 6 is a plan view showing a state where the insulation tape isplated;

[0020]FIG. 7 is an enlarged cross section of a part of the platedinsulation tape; and

[0021]FIG. 8 is a cross sectional view showing a semiconductor deviceaccording to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022]FIGS. 2 and 3 are diagrams showing a semiconductor chip mountingtape according to the invention. FIG. 2 is a plan view and FIG. 3 is across sectional view. These diagrams are shown in a state where the backside of the semiconductor chip mounting tape faces upward.

[0023] A plurality of external connecting terminals 12 are arranged onthe back side (second surface) of a film-like insulation tape 11 madeof, for example, polyimide in accordance with a layout pattern which hasbeen predetermined for a plurality of semiconductor chips.

[0024] A plurality of post portions 13 to be electrically connected tobonding pads formed on the semiconductor chips by wire bonds are formedon the surface (first surface) of the insulation tape 11.

[0025] The external connecting terminal 12 and post portion 13 areintegrally formed by the same solder ball via a through hole formed inthe insulation tape 11.

[0026]FIG. 4 is an enlarged cross sectional view of a part of thesemiconductor chip mounting tape shown in FIGS. 2 and 3. The diagram isshown in a state where the second surface of the insulation tape 11faces upward.

[0027] Through holes 14 are formed in the insulation tape 11 and plating15 is performed to opening portions of the through holes, namely, wallportions of the through holes 14 and hole peripheral portions on bothsides of the insulation tape 11.

[0028] The external connecting terminals 12 are formed on the secondsurface of the insulation tape 11 and the post portions 13 are formed onthe first surface in a manner such that the external connectingterminals 12 and the post portions 13 are integrally formed by the samesolder balls 16 exposed to both sides of the insulation tape 11 via thethrough holes 14.

[0029] The solder ball 16 is fixed to the insulation tape 11 through theplating 15 by ref lowing.

[0030] According to the semiconductor chip mounting tape by theinvention as mentioned above, since the solder balls 16 are embeddedinto the through holes 14 and the external connecting terminals 12 andpost portions 13 are formed, the external connecting terminals 12 can bepositively formed on the insulation tape 11.

[0031] FIGS. 5 to 7 are diagrams for explaining a manufacturing methodof the semiconductor chip mounting tape shown in FIGS. 2 to 4. FIG. 5 isa plan view showing an insulation tape in which through holes areformed. FIG. 6 is a plan view showing a plated insulation tape. FIG. 7is an enlarged cross sectional view of a part of the plated insulationtape.

[0032] In FIG. 5, the circular through holes 14 slightly smaller thanthe diameter of the solder balls are formed in the prepared insulationtape 11 in accordance with a predetermined layout pattern of theexternal connecting terminals.

[0033] In FIGS. 6 and 7, the plating 15 is performed to the openingportions of the through holes 14. Specifically, the wall portions of thethrough holes 14 and hole peripheral portions on both sides of theinsulation tape 11 is performed by electrolyte-free plating or the like.

[0034] Subsequently, flux is deposited onto the second surface of theinsulation tape 11, for example, the lower surface of FIG. 7 by dipping.The method of depositing the flux is not limited to the dipping methodbut the flux can be also deposited by any of such methods astransferring and coating.

[0035] The second surface of the insulation tape 11 on which the flux isdeposited is set so as to face upward and the solder balls 16 aremounted to the through holes 14 by a ball mounter as shown in FIG. 4.

[0036] By allowing the tape to pass through a reflow furnace, the solderballs 16 are reflowed, thereby fixedly bonding the solder balls 16 ontothe insulation tape 11 through the plating 15 as shown in FIG. 4.

[0037] The external connecting terminals 12 are, consequently, formed tothe second surface of the insulation tape 11 and, at the same time, apart of each of the solder balls 16 is exposed to the first surface ofthe insulation tape 11 via the through hole 14 as shown in FIG. 4,thereby forming the post portion 13.

[0038] In the manufacturing method of the semiconductor chip installingtape according to the invention as mentioned above, since the flux isnot directly transferred to the solder balls 16, no flux is deposited tothe vacuum plate and the solder balls 16 can be positively mounted tothe insulation tape 11.

[0039] Since the flux is sufficiently deposited to the plated portionsof the insulation tape 11 by dipping or the like, the solder balls 16 donot drop due to the non-fused state of the soldering.

[0040] Further, since the external connecting terminal 12 and postportion 13 are simultaneously formed from the same solder ball 16, themanufacturing time can be shortened. Differing from the conventionalsubstrate, it is possible to omit the copper foil sticking step for thecircuit pattern, the wiring step of wiring the post portions andexternal terminals of the substrate, the soldering resist coating stepof protecting the circuit pattern, and the like.

[0041]FIG. 8 is a cross sectional view showing a semiconductor deviceaccording to the invention and shows a BGA package using a semiconductorchip mounting tape with external connecting terminals according to theinvention.

[0042] A semiconductor chip 17 is mounted on the surface of asemiconductor chip mounting tape in which the post portions 13 areformed on the first surface of the insulation tape 11 by solder balls 16and the external connecting terminals 12 are formed on the secondsurface by the same solder balls 16. The semiconductor chip 17 is fixedwith an adhesive 18.

[0043] Pads 19 formed on the semiconductor chip 17 and the post portions13 are wire-bonded by bonding wires 20 such as gold wires or the likerespectively, thereby resin-sealing the wire-bonded portions and thesemiconductor chip 17 by a resin 21. The wire-bonded portions of thepost portions 13 and a joint interface between the semiconductor chip 17and insulation tape 11 are, therefore, protected by the resin-sealing.

[0044] Although the semiconductor device of the BGA package is attachedonto an installing substrate (not shown) by reflowing the solder balls16, in this instance, even if the solder is fused, since the wire-bondedportions are resin-sealed, there is no fear such that the wires 20 arepeeled off from the post portions 13.

[0045] As mentioned above, in the second embodiment according to theinvention, the BGA package with the external connecting terminals inwhich the diameter of the solder balls is small and a pitch is narrowcan be realized by using the semiconductor chip mounting tape accordingto the invention.

[0046] Since the semiconductor chip mounting tape is thinner than thatof the conventional substrate, a package which is thinner by an amountcorresponding to the thin tape can be formed.

[0047] Subsequently, a manufacturing method of the semiconductor deviceaccording to the invention will now be described. First, thesemiconductor chip mounting tape according to the invention is prepared.The semiconductor chip mounting tape is constructed so as to have alength such that a plurality of semiconductor chips can be installedsimultaneously.

[0048] As shown in FIG. 8, the first surface of the insulation tape 11formed with the post portions 13 is set so as to face upward, and thesemiconductor chip 17 is die-bonded at a predetermined position on thefirst surface. The semiconductor chip 17 is fixed onto the insulationtape 11 by the adhesive 18.

[0049] Subsequently, the pads 19 formed on the semiconductor chip 17 andthe post portions 13 are electrically connected by the wire-bondingmethod by using the wires 20.

[0050] After that, the wire-bonded portions and the semiconductor chip17 are resin-sealed with the resin 21.

[0051] Since the manufacturing process is executed on the semiconductorchip mounting tape and a plurality of semiconductor devices aremanufactured, the semiconductor chip mounting tape is cut and the BGApackage is segmented, thereby completing the manufacturing method.

[0052] According to the method of fabricating the semiconductor deviceof the invention as mentioned above, since the manufacturing step of thesemiconductor chip mounting tape is remarkably shortened, themanufacturing time of the semiconductor device can be also reduced.

[0053] According to the invention as mentioned above, since the postportions and external connecting terminals which are connected to thesemiconductor chip via the through holes formed in the insulation tapeare integrally formed, the external connecting terminals can becertainly formed to the insulation tape.

What is claimed is:
 1. A semiconductor chip mounting tape on whichexternal connecting terminals are formed in accordance with a layoutpattern, comprising: an insulation tape having through holes; postportions which are to be connected to a semiconductor chip, said postportions formed on a first surface of an insulation tape; and externalconnecting terminals formed on a second surface of said insulation tape,wherein said post portions and said external connecting terminals areintegrally formed via said through holes of said insulation tape.
 2. Amethod for fabricating a semiconductor chip mounting tape, comprisingthe steps of: forming through holes which are slightly smaller than adiameter of solder balls in an insulation tape in accordance with alayout pattern of external connecting terminals; performing plating toopening portions of said through holes; depositing a flux onto a secondsurface of said insulation tape; depositing solder balls to said throughholes by setting the second surface of said insulation tape so as toface upward; and reflowing said solder balls, forming the externalconnecting terminals onto the second surface of said insulation tape,and at the same time, forming post portions which are to be connected toa semiconductor chip on a first surface of said insulation tape.
 3. Asemiconductor device according to claim 1, wherein a semiconductor chipis mounted on said semiconductor chip mounting tape according to claim1, said semiconductor chip having pads for electrical connection, saidpads and said post portions bonded with wires, and wire-bonded portionsand said semiconductor chip are sealed with a resin.
 4. A method forfabricating a semiconductor device according to claim 1, comprising thesteps of: preparing said semiconductor chip mounting tape according toclaim 1; die-bonding a semiconductor chip onto said semiconductor chipmounting tape; bonding pads on said semiconductor chip and said postportions by wires; sealing said wire-bonded portions and saidsemiconductor chip by a resin; and segmenting said resin-sealed package.